Overall Green Flood
in Sri Lanka

Flood impact summary

This flood is expected to have a low humanitarian impact based on the magnitude and the affected population and their vulnerability.

GDACS ID: 1103900
Deaths: 1
Displaced: 3485
Region: North Western Province, Sabaragamuwa Province, Western Province, Gampaha District, Ratnapura District, Colombo District, Puttalam District
Countries: Sri Lanka
From - To 08 May - 23 May
Known identifiers for this event:

GDACS Score

For more info on GDACS score click here.

Impact Assessement as of 26-05-2026

SENDAI Indicator A N Country Location Info
death 1 Sri Lanka Gampaha District
SENDAI Indicator B N Country Location Info
affected 133 Sri Lanka Monaragala
affected 22 Sri Lanka Opanayake
affected 95 Sri Lanka Batticaloa
affected 3 Sri Lanka Mullaitivu
affected 6773 Sri Lanka Colombo District
affected 14441 Sri Lanka Gampaha District
affected 529 Sri Lanka Kalutara
affected 4265 Sri Lanka Puttalam District
affected 1469 Sri Lanka Colombo
affected 3704 Sri Lanka Ratnapura District
affected 4 Sri Lanka Nuwara Eliya
displaced 497 Sri Lanka Colombo District
displaced 1670 Sri Lanka Gampaha District
displaced 1264 Sri Lanka Puttalam
displaced 54 Sri Lanka Ratnapura District
injured 1 Sri Lanka Colombo District
SENDAI Indicator C N Country Location Info
houses damaged 6 Sri Lanka Colombo District
houses damaged 568 Sri Lanka Gampaha District
houses damaged 186 Sri Lanka Puttalam District
houses damaged 64 Sri Lanka Ratnapura District

Satellite Observation

Satellite-based Flood extent provided by GLOFAS
Overall of the satellite-based flooded area from / to : 2026-05-01 / 2026-05-30  

Friday 01/05Saturday 02/05Sunday 03/05Monday 04/05Tuesday 05/05Wednesday 06/05Thursday 07/05Friday 08/05Saturday 09/05Sunday 10/05Monday 11/05Tuesday 12/05Wednesday 13/05Thursday 14/05Friday 15/05Saturday 16/05Sunday 17/05Monday 18/05Tuesday 19/05Wednesday 20/05Thursday 21/05Friday 22/05Saturday 23/05Sunday 24/05Monday 25/05Tuesday 26/05Wednesday 27/05Thursday 28/05Friday 29/05Saturday 30/05

Timeline of revisions

For accessing reports of previous advisories, please click on the advisory number in the table below.

IDLevelPopulation affectedStart DateEnd DateSource
1 0 deaths and 1264 displaced 08 May 2026 17 May 2026 GLOFAS
2 1 deaths and 2221 displaced 21 May 2026 23 May 2026 GLOFAS

Flood polygons

This polygon (translucent blue with a blue border) is drawn by the analysts recording the flood event. It is meant to include all the areas reported as affected, by official source or the media. It does not represent the area actually under water.

Microwave flood detection

Flooded area, as detected in microwaves by the Global Flood Detection System of the JRC, based on NASA TRMM/GPM observations. This system has a rather low resolution (of 5-10km) but is not affected by clouds.
For more details, see http://www.unisdr.org/files/9622_LBNA23303ENC002.pdf.
The areas with a flood signal along the coast are an artefact of the system and should not be considered.

Optical Flood detection

Flooded area as detected in optical wavelengths by NASA/MODIS, known as "MODIS Flood Product". Data are made available by NASA GSFC Flood Mapping Project, http://oas.gsfc.nasa.gov/floodmap/index.html. Resolution of 250m, heavily affected by cloud cover.